In 1997, the Center for Interdisciplinary Research on AIDS (CIRA) received a P01 Program Project grant from NIMH and NIDA to conduct research aimed at the prevention of HIV infection and reduction of the negative consequences of HIV disease in vulnerable and underserved populations. We successfully competed for a five-year P30 CSPAR grant in September 2001. With this application, we seek to renew this CSPAR grant for an additional 5 years of support. Over the past 4 years, a total of 82 externally funded research and training grants (60 research, 22 training) have been affiliated with the Center; 37 (28 research) of these are currently ongoing. Five additional research grants are currently pending award. A total of 31 scientists have served as Principal Investigators on these different projects. An additional 23 have been awarded funds through our pilot project program during this same period. CIRA affiliated research will continue to identify the determinants of risky behaviors in vulnerable populations, develop and assess interventions to address this risk, analyze policy, laws, and structures associated with risk and prevention, and examine the global dimensions of the pandemic. In addition, we will support the conduct of translational research and ethics research. Wherever possible, this research will be interdisciplinary in nature, drawing from the full range of theoretical and methodological expertise of CIRA scientists, who together, represent 16 different disciplines. Six Cores will support the conduct of research in these areas. An Administrative (Admin) Core will serve as the planning and decision-making body and will provide overall scientific leadership, and administrative management. A Development (Dev) Core will provide mechanisms for promoting and supporting new research and bringing new scientists, at all stages in their careers, to HIV/AIDS research. An Interdisciplinary Research Methods (IRM) Core will provide consultations, hands-on assistance, resources, and training in quantitative methods and biostatistics, qualitative methods and ethnography, and cost effectiveness and mathematical modeling. The Community Research (CR) Core will facilitate community-based and translational research by CIRA scientists, build research capacity of community partners, and facilitate the dissemination of research findings. An International Research (IR) Core will foster the development of new international HIV/AIDS research consistent with CIRA's mission, and provide technical support and expertise for ongoing research. The Law, Policy, and Ethics (LPE) Core will facilitate the development of new and support ongoing research with a legal, policy, ethics, or structural focus. It will also ensure that CIRA research meets the highest ethical and legal standards and that it is accessible to policymakers.